The proposed research plan is directed to determine how complex movements involving several joints are organized and controlled. The role of sensory inputs and the participation of cortical and cerebellar activities in these processes will be examined from a quantitative viewpoint. Human subjects and trained monkeys with discrete lesions will be used. In particular we shall investigate nonlinear and adaptive aspects of the relationship between sensory input and motor output, the hypothesis that skilled movements are realized by creating synergies between different muscle groups and the role of sensory inputs in the generation and implementation of learned, skillful motor sequences.